A large body of research has been interpreted as showing that formal grammar instruction does not lead to better student writing. This literature review questions the conclusiveness of the evidence that is usually cited. The term "formal grammar instruction" has been one source of problems; most studies have failed to distinguish between a body of grammatical principles and a method of teaching those principles. Correlational studies are examined and found to have contradictory results, as well as to provide no indication of causal relationships. Finally, four experimental studies that compared one instructional method to another are reviewed and found to have weaknesses in design or interpretation. On the basis of these findings, the author concludes that the question of the relationship of grammar instruction to writing has not been conclusively resolved. (AA)